London: Graeme Swann's criticism of Kevin Pietersen in his autobiography has not affected their friendship, insisted England cricket coach Andy Flower but conceded that he would have wanted the off-spinner to wait till retirement before writing such a book.

In his autobiography, Swann had criticised Pietersen's captaincy stint, saying that he was a bad choice to lead England in 2008 and 2009.

Flower praised Pietersen for his "mature handling" of the situation and hoped that such tell-all books are kept for after the retirement.

Asked whether he believes players should wait until retiring to air such revelations in print, he said: "That's my personal opinion, yes."

"I personally don't think that it's a good idea for current players to be talking about their fellow players," Flower said.

"The written word does come across very, very differently - when you can't judge a person's tone - and particularly with Swann's words, that is an accurate and important point."

Flower insisted that England's team spirit was intact despite the controversy.

"It's all been handled in-house - without many problems. Pietersen and Swann get on well, and I think Pietersen has handled it very maturely," he said.

England, touring India right now, are down 0-1 in a five-match ODI series.